Primer for internal combustion engine



y 3, 1951 T. A. SEEGRIST 2,985,161

PRIMER FOR INTERNAL COMBUSTION ENGINE Filed Oct. 30, 1960 FIG. 1.

FIG. 2.

97 d. W VENTOR United States Patent 2,985,161 PRIMER FOR INTERNAL COMBUSTION ENGINE Theodore A. Seegrist, Box 223, McLean, Va.

Filed Oct. 20, 1960, Ser. No. 63,864

5 Claims. (Cl. 123-180) This invention relates to means especially adapted for priming a two-cycle internal combustion engine as an aid to starting the engine and has among its objects provision of structure which is economically added to the usual liquid fuel (gasoline) supply system of the engine, and which is simple to operate.

Essential features of the engine and primer are illustrated in the accompanying drawing in which:

Fig. 1 is a schematic illustration, and

Fig. 2 is a sectional view of a pressure relief valve and connections used with the priming means.

The usual two-cycle internal combustion engine is provided with a crankcase 5, a carburetor having an air intake 7 and manifold 8 leading from the carburetor to the crankcase, the air-flow passage into the crankcase 1 being through the air intake and manifold, gasoline being jetted into the air-flowpassage from the carburetor bowl 9 through the carburetor high speed needle valve 10 and low speed needle valve 11, the float 1'2, float valve 13, throttle valve 14 and choke valve 15 performingtheir normal functions. 1

These engines are frequently difficult to start, especially When cold, since the air-fuel mixture must charge through the crankcase before it is admitted into the engine cylinder for compression and combustion. Thus extended choking is required and it may be necessary to open the high speed needle valve considerably more than desired for normal operation of the engine and to crank the engine an excessive number of turnovers before a sulficiently rich air-fuel mixture will be fed to the engine cylinder to result in ignition and start of the engine. Furthermore, because of the choking the air supply rate is diminished, thus diminishing the rate the air-fuel mixture is delivered to the crankcase and increasing the number of turnovers'required tosupply a sutlicient quantity of air-fuel mixture into the crankcase to start the engine.

After the engine starts, it is necessary to reset the needle valve to its proper feeding rate for normal running if best engine performance is to be obtained. Many persons who operate the engines are not capable to, or will not bother to, make the required adjustments.

A two-cycle engine in common use for an outboard motor is provided with a carburetor system equipped with an atmospherically vented fuel-supply tank 20, which may be separated from the engine for filling and carrying, the tank having a flexible hose 21 as part of the fuelline communicating with the bottom of the tank. The free end of the hose is provided with one member 22 of a two member hand coupling, member 22 having an internal normally closed valve such as a ball gate 23 pressed into engagement with an appropriate valve seat by a spring 24.

The other member 25 of the coupling, which member is normally fixed to the engine, has a nozzle portion 26 which enters member 22 when the coupling members are hand coupled together, the end of the nozzle contacting the ball gate to open the valve. Thus, with the coupling onto the motor, the fuel-line, fuel pump, and carburetor bowl may be filled or partially filled with air. In order to withdraw fuel from the fuel-tank and force the .fuel

under pressure through the fuel-line to the carburetor to purge the system of air and fill the required parts with fuel, a hand operated pump 35 is normally positioned in the-.hose 21. As a usual structure the hand-pump is a hand compressible bulb of resilient material provided with valves 36 and 37. Hand pressure on the bulb to 4 collapse it empties the bulb through valve 37 while valve 36 remains closed and release of the pressure permits. 2 the bulb automatically to expand to fill it throughvalve 36 while valve 37 remains closed.

In some structures the air vents automatically through In other structures an air-vent v the carburetor bowl. valve, which may be hand operated, is provided. In any structure, once the air is purged from the system and the system is filled with fuel any further attempt to operate the hand-pump 35 builds up pressure in that portion of the fuel-line on the pressure side of the handpump.

The structures above described are conventional. The present invention involves addition of a springclosed pressure relief valve 50, such as one having a valve gate 51 seated on a valve seat 52 made of oil resistant hard rubber like material, the valve b'eing normally maintained closed by a compression spring 53 pressing the gate into seating position on the valve seat.

The inlet of the pressure relief valve communicates with the fuel-line on the pressure side of the hand pump, as r for example by being inserted in section 30 of the fuel line, while the outlet communicates, asby a pipe '60, with the crankcase, preferably through the air-flo'w passage of T As illustrated in Fig. 2, pipe 60 is connected to the pressure relief valve with a conventional" the carburetor.

sealing bushing 61 of soft material such as copper compressed into place by nut 62. Nut 63 is screw threaded into connector 64, seals against seat 52, and holds the valve gate 51 and spring 53 in place.

In use, priming of the engine is accomplished simply by pumping of hand-pump 35 in addition to the pumping required to purge the system of air and fill the fuel-line and carburetor with fuel. Preferably spring 53 is selected of a tension such that the pressure relief valve will open only by a noticeable build up of the pressure in the fuel-line by additional operation of the hand-pump I after the system has'been purged of air and filled with fuel. Thus the operator can easily determine by the feel of the hand-pump when the system has been air purged and when the priming fuel is being forced through the pressure relief valve.

As illustrated in Fig. l, pipe 60 feeds priming gas directly into air intake 7. This is a convenient structure, especially in case the air intake opens upwardly, and is operationally desirable since it provides efficient mixing of the raw priming fuel with the air as the air flows through the air-flow passage of the carburetor and into the crankcase.

Other points of entry of the fuel from the pipe 60 may be provided so long as the fuel is eventually admitted into the crankcase, for example by connecting the pipe 69 into the manifold 8.

The choke valve can be omitted if desired since primtank, the tank being provided with a flexible hose leading from the tank to one member of a hand coupling adapted to be coupled to a second member of the coupling fixed to the engine and communicating through a fuel-line with the carburetor thus to connect the tank to the carburetor for supplying fuel thereto, the hose having a hand operated pump therein for withdrawing fuel from the tank and forcing the fuel under pressure through the fuelline to purge air from the fuel-line and carburetor and fill them with fuel preparatory to starting the engine, the engine being provided with a spring-closed pressure relief valve, the intake of the pressure relief valve communicating with the fuel-line on the pressure side of the pump and the outlet of the pressure relief valve communicating with the air-flow passage of the carburetor, the spring pressure of the pressure relief valve being such that the hand operated pump may be operated to purge air from the fuel-line and carburetor and fill them with fuel and further operation of the pump will cause the pressure relief valve to open and feed priming fuel into the air-flow passage.

2. A two-cycle internal combustion engine having a carburetor with an air-flow passage for supplying a gasair mixture into the crankcase of the engine, an atmospherically vented liquid fuel-supply tank, a fuel-line leading from the tank to the carburetor, and a hand operated pump in the fuel-line for withdrawing fuel from the tank and forcing the fuel under pressure through the fuel-1i ne to purge air from the fuel line and carburetor and fill them with fuel preparatory to starting the engine, the engine being provided with spring-closed pressure relief valve, the intake of the pressure relief valve communicating with the fuel-line on the pressure side of the pump and the outlet of the pressure relief valve communicating with the air-flow passage of the carburetor, the spring pressure of the pressure relief valve being such that the hand operated pump may be operated to purge air-from the fuel-line and carburetor and fill them with fuel and further operation of the pump will cause the pressure relief valve to open and feed priming fuel'into the air-flow passage.

3. A carburetor system having an air-intake and a manifold providing an air-fiow passage for supplying an air-fuel mixture to an internal combustion engine, a fuelsupply tank, a fuel-line connecting the fuel-supply tank with the carburetor, a hand operated pump in the fuelline for withdrawing fuel from the fuel-supply tank and forcing the fuel under pressure through the fuel-line to purge air from the fuel-line and carburetor and fill them with fuel preparatory to starting the engine, and a springclosed pressure relief valve, the intake of the pressure relief valve communicating with the fuel-line on the pressure side of the hand operated pump and the outlet of the pressure relief valve communicating with the airflow passage of the carburetor system, the spring pressure of the pressure relief valve being such that the hand operated pump may be operated to purge air from the fuelline and carburetor and fill them with fuel and further operation of the pump Will cause the pressure relief valve to open and feed priming fuel into the air-flow passage.

4. An outboard motor having a two-cycle internal combustion engine, a carburetor with an air-flow passage for supplying an air-gas mixture into the crankcase of the engine, one member of a hand coupling fixed to the motor, communicating through a fuel-line with the carburetor for supplying fuel to the carburetor from a fuel-supply tank equipped with a flexible hose leading'from the fuel-supply tank to a second member of the hand coupling, thus to connect the tank to the carburetor for supplying fuel thereto When the coupling members are coupled together, said flexible hose vhaving a hand operated pump therein for withdrawing fuel from thetank and forcing the fuel under pressure through the fuel-line to purge air from the fuel-line and carburetor and fill them with fuel preparatory to starting the engine, and a spring-closed pressure relief valve, the intake of which communicates with the fuel-line and the outlet of which communicates with the air-flowpassageof the carburetor, the spring pressure of the pressure relief valve being such that the hand operated pump may be operated to purge air from the fuel line and carburetor and fill them with fuel and further operation of the pump will cause the pressure relief valve to open and feed priming fuel into the airflow passage.

5. A spring-closed pressure relief valve for insertion in the fuel-line of a carburetor system having an air intake and a manifold providing an air flow passage for supplying an air-fuel mixture to an internal combustion engine, a fuel-supply tank, a fuel-line connecting the fuel- I supply tank with the carburetor and a hand operated pump in the fuel-line for withdrawing'fuel from thefuelsupply tank and forcing the fuel under pressure throughthe fuel-line to purge air from the fuel-line and carburetor and fill them with fuel preparatory to starting the engine, the intake of the pressure relief valve being adapted to communicate with the fuel-line on the pressure side of.

the pump and the outlet of the pressure relief valve being adapted to communicate with the air-flow passage, i

the, spring pressure of the pressure relief valve being such that the hand operated pump may be operated to purge air from the fuel-line and carburetor and fill them with fuel and further operation of the pump will cause the pressure relief valve to open and feed priming fuel into the air-flow passage.

References Cited in the file of this patent UNITED STATES PATENTS 

